Turkey's military operations against Kurdish guerrillas in northern Iraq will last another three or four days, a senior Turkish official said yesterday, after Washington called for a speedy end to the incursion.

Hours after the US defence secretary, Robert Gates, said Turkey must be "mindful of Iraqi sovereignty" and should not extend its operations longer than a week or two, the Turkish official said the cross-border operation would be over by next week. "Ten days will be a good enough time for the operation. It has been going on now for six or seven days, so another three or four days should wrap it up," the official said.

The bulk of the troops would be pulled back, he added, leaving an uninhabited cordon sanitaire on the south side of the border. In official comments so far, Turkish officials have refused to give a timetable for the operation, saying it would end when Kurdish guerrilla bases in Iraq had been uprooted.

The Turkish official, speaking on condition of anonymity, also claimed that the Iraqi government in Baghdad had consented to the offensive against forces of the Kurdistan Workers party (PKK) because it was unable to stop them launching cross-border raids on Turkey.

He said that before the assault began last Thursday there were substantial conversations between Turkey's president, Abdullah Gul, and his Iraqi opposite number, Jalal Talabani, and between the prime ministers of the two countries. In those conversations, the official said, the Iraqi leaders gave a green light.

"Iraq has been busy with security in the rest of the country, and they know that this [the PKK presence on Iraqi soil] was beyond their means at the moment," he said. The Baghdad government has committed itself, on Turkish and US insistence, to closing down PKK camps in the north, but has largely been blocked by the autonomous Iraqi Kurd administration there, which has refused to use its "peshmerga" fighters against fellow Kurds.

Iraqi officials in Baghdad have denied giving approval for the Turkish operations and have demanded an immediate Turkish withdrawal.

"We condemn the terrorists and the PKK, but we also condemn the violations of the sovereignty of Iraq at the same time and we have to be very clear on that," the Iraqi foreign minister, Hoshyar Zebari, said after meeting a Turkish envoy, Ahmet Davutoglu.

Turkey claims it has killed 230 PKK fighters, with the loss of about two dozen of its own soldiers. The PKK, which is fighting for Kurdish autonomy in southeastern Turkey, says only a handful of its guerrillas have been killed, at the cost of 80 Turkish troops. The claims cannot be confirmed as the fighting is taking place in remote mountains along the border.

The Turkish official said 35% of PKK fighters were Syrian Kurds and complained that Damascus appeared to exercise little control over its border. However, he said there was limited intelligence cooperation with both Syria and Iran, who both have Kurdish minorities.

Gates headed for Ankara yesterday carrying a message from Washington calling for a quick withdrawal. "It's very important that the Turks make this operation as short as possible and then leave," he said before leaving India for Turkey. "They have to be mindful of Iraqi sovereignty. I measure quick in terms of days, a week or two, something like that, not months."